Noa has a higher AVERAGE crazy, but Mikoto has a much higher quantity.
Everybody in Noa is running at like a 8/10 to 11/10 on the crazy scale. The whole world in Mikoto seems to be simmering at a solid 4/10 to 6/10 craziness.
Most of Rihito's and Noa's coworkers are perfectly sane, though! That brings down the average at least to some degree.
And in Mikoto-chan, there are 8+ insanity types as well (both of the moms come to mind), though admittedly, neither of the MCs is anywhere near Noa in terms of unhingedness. And the whackadoodle with the loosest screws of all in either series is easily Reni, so I definitely have to agree Noa-senpai has the edge in peak insanity.
You could certainly argue either way. I do think this chapter of Mikoto-chan is a major paradigm shift. Before it I assumed the insanity was mostly contained within the class president, but now there's definitely an impression that the entire class is taking a little more of a personal interest in Mikoto's love life than is entirely healthy.